Johnson & Johnson Covid-19 Vaccine On Hold

Johnson & Johnson paused their late-stage COVID-19 vaccine trial due to an unexplained illness in a participant. Such pauses are common to assess potential side effects. The participant's condition is being evaluated by independent and internal safety boards. This is the second COVID-19 vaccine trial pause, following AstraZeneca's trial halt due to a neurological condition. The FDA is investigating. Meanwhile, a second wave of COVID-19 cases is expected in the US, with hospitals in the UK already experiencing a surge. Despite the pauses, other US vaccine candidates continue in late-stage trials.

What was the reason for Astra Zeneca's trial being put on hold?

How is the current situation regarding COVID-19 cases in the UK described?